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46Re: [beemonitoring] Bombus-GroundIvy Connection?

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  • David Inouye
    Dec 21, 2006
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      That's interesting that bees of all those proboscis lengths will use the same flower.  Quantitative data on frequency of use by each of those species would be interesting. Bumble bees will investigate a wide range of flowers, in my experience, but typically settle quickly on those that are a good morphological match and rewarding.

      The 5.8mm measurement for terrestris/lucorum sounds short to me.  I've seen data reporting them as about 8 mm, which then puts them in a different category from honey bees.

      At 02:13 PM 12/21/2006, you wrote:

      According to the British bumbleebee researcher I contacted, (at least) four true British Bumblebee species are known to visit Glechoma hederacea; Bombus pascuorum (most frequent), B.lucorum , B.pratorum, and B.hortorum. 
       
      Each of the four British species are listed in the "tongue length" table below.  Dr Inuoye suggested a correlation between Bombus proboscis length and use of G. hederacea.  Is that corroborated by the data I provided?
       
      Average tongue lengths mesured from foraging bumblebee workers.
      Species
      Tongue length mm
      Bombus hortorum
      12.0
      Bombus lapidarius
      6.0
      Bombus pascuorum
      7.6
      Bombus pratorum
      6.4
      Bombus terrestris/lucorum
      5.8

      (Table source: http://www.bumblebee.org/bodyTongue.htm)


      On 12/19/06, David Inouye <inouye@...> wrote:

      At 04:45 PM 12/19/2006, you wrote:

      >Background 1: In my Baltimore City neighborhood, and in many urban
      >areas, Ground Ivy (Glechoma hederacea) is now one of the most
      >important flowers for bumblebees in part because of its early season
      >bloom and because of its vast abundance and wide distribution.
      >
      >Question 1: Before Europeans arrived, while the indigenous people
      >were "managing" the landscape, what early season flower species did
      >the native bumblebee spp depend on?

      Depends on their proboscis length.

      >Background 2: (a) Wikipedia says, "In Britain, until relatively
      >recently, 19 species of native true bumblebee were recognised..."
      >(b) The Wisconsin Bumblebee regional chart lists 4 species native to Maryland.
      >
      >Question 2a: If Ground Ivy evolved in close relationship with
      >British bombus species, then the Ground Ivy we see today may be the
      >result of the selective pressure of associating with up to 19
      >bumblebee species? Wouldn't that make Ground Ivy a super bumblebee flower?

      It is unlikely that all 19 species would have foraged on a single
      plant species. The relationship between bees and plants is typically
      mediated by an appropriate match between proboscis length and corolla
      tube length, so probably only one subset of the three categories of
      proboscis length would have visited the flowers.

      >Question 2b: So now consider the possibility that our native North
      >American bombus species also prefers Glechoma hederacea because it
      >is a super bombus food. What impact on the distribution of Ground
      >Ivy would result from this preference by our native bombus
      >spp? Would an adopted preference for Ground Ivy by N.A. bombus spp
      >impact any other native/non-native early spring flowering plants
      >which may be blooming in the vicinity? And if so, in what way(s)?
      I suspect this plant is not limited by seed production and dispersal,
      so the effects of native Bombus on the introduced plant are probably
      minimal. There probably is the potential for ground ivy to have a
      negative impact on visitation to (and thereby seed set of) some
      native plants that flower at the same time.

      Dr. David W. Inouye, Director
      Graduate Program in Sustainable Development and
      Conservation Biology
      Room 1201, Biology/Psychology Building
      University of Maryland
      College Park, MD 20742-4415
      301-405-6946
      inouye@...
      FAX 301-314-9358

      For the CONS home page, go to http://www.umd.edu/CONS


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